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Biomedical subjects

T Inokuchi

Publications and source records attributed to T Inokuchi.

At least 55 records · Page 3Linked to original sources

A case of oromandibular-digital hypogenesis syndrome.

The oromandibular-digital hypogenesis syndrome is characterized by failure of development of the intraoral region and the distal extremities. A 12 year old female with an anomaly of the lingual fraenum, hypodontia of the lower incisors and defective fingers and toes was referred to our clinic. The aetiology of the disorder is still obscure. The author has reviewed the literature and discusses the morphological variation of the lingual fraenum.

Abnormalities, Multiple

Scanning and transmission electron microscopic study of the ampullary region of the dog vas deferens, with special reference to epithelial phagocytosis of spermatozoa and latex beads.

The present SEM and TEM study clearly indicated that the epithelial cells of the ampulla vasis deferentis of the dog are capable of performing phagocytosis of degraded spermatozoa and even inert latex beads as in other animals described previously and further supported our working hypothesis that epithelial phagocytosis may be a common event in the vas deferens of mammals, though its precise significance remains to be clarified.

Animals

Brown adipose tissue lipectomy leads to increased fat deposition in Osborne-Mendel rats.

Inter- and subscapular brown adipose tissue depots were removed from nine female Osborne-Mendel rats. These lipectomized animals and nine sham-operated controls recovered from surgery for 7 days at 25 degrees C and were then placed on a highly palatable liquid diet. All animals were maintained for a 2nd wk at 25 degrees C before being switched to 8 degrees C. After 9 wk in the cold, animals were killed, and the brown adipose tissue was dissected from scapular, cervical, thoracic, perirenal, and axillary regions. Total brown fat pad mass, protein content, brown adipocyte number, citrate synthase activity, and beta-hydroxyacyl CoA dehydrogenase activity in each of the dissected brown fat depots were significantly less than those of the sham-operated controls. Thus there was incomplete metabolic compensation in the remaining brown fat depots after the removal of the scapular brown fat in the lipectomized rats. The mass and lipid content of the retroperitoneal white adipose depot were significantly increased in the lipectomized rats as was their carcass fat content (up 14%). Food intake of the lipectomized rats was slightly but significantly decreased. These data indicate that a reduction in the amount of functional brown fat is accompanied by increased body fat accretion and are thus consistent with the hypothesis that decreased brown adipose thermogenesis can lead to altered energy balance and increased white fat deposition.

3-Hydroxyacyl CoA Dehydrogenases

[Effect of 4-(o-benzylphenoxy)-N-methylbutylamine hydrochloride (bifemelane hydrochloride, MCI-2016) on cerebral glucose metabolism].

To predict the influence of MCI-2016 on cerebral energy metabolism, the activity of MCI-2016 on uptake of 2-deoxy-D-[14C]glucose ([14C]-DG) into the brain under normal or hypoxic conditions, formation of 14CO2 from 14C-glucose in the brain, and local cerebral glucose utilization (LCGU) were examined. Cerebral uptake of [14C]-DG in mice were significantly enhanced by 6 day repeated administration of MCI-2016 (25 mg/kg, i.p.) and Ca-hopantenate (100 mg/kg, i.p.). The two drugs showed a slight enhancing effect on [14C]-DG uptake after single administration. As an index of cerebral glucose metabolism, 14CO2 formation from 14C-glucose was also stimulated by 6 day repeated administration of MCI-2016 (100 mg/kg, p.o., mice and rats) and Ca-hopantenate (250 mg/kg, i.p., rats). MCI-2016 moderately attenuated the decreased [14C]-DG uptake under the hypoxic condition in rats after 6 day repeated administration (100 mg/kg, p.o.). In addition, local cerebral glucose utilization (LCGU) in rats was also significantly potentiated by MCI-2016 (100 mg/kg, p.o., 6 days) in the areas of the visual cortex, thalamus ventral nucleus and uvula. From these results, MCI-2016 may be suggested to have a moderate activating effect on cerebral energy metabolism.

Administration, Oral

Phagocytosis of spermatozoa and latex beads by epithelial cells of the ampulla vasis deferentis of the rabbit: a combined SEM and TEM study.

The fine structure in the ampullary region of the vas deferens of the rabbit was observed by scanning and transmission electron microscopy, with emphasis on the occurrence of epithelial spermiophagy. The epithelial cells were cuboidal or low columnar and contained moderately developed organelles. These cells, like luminal macrophages, were found to be not only involved in spermiophagy but also capable of actively taking up latex beads administrated intraluminally. Taking into consideration the previous findings in some other species, the epithelial spermiophagy seems to be a common event in the vas deferens of mammals.

Animals

Three-dimensional profile of three types of spermatogonia and their topographies in adolescent or adult rats.

Stereomorphic profiles of three types of spermatogonia and their topographical distribution in the basal portion of the seminiferous epithelium of adolescent or adult rats were studied mainly with the scanning electron microscope. According to their cytological features, three types of spermatogonia (large-sized and long fusiform or polygonal; medium-sized and elliptical; small-sized and round) were discerned in both groups of rats. The basal areas of the three spermatogonia were relatively smaller in the adolescent rats than in the adult rats. The type of spermatogonia in the adolescent rats varied somewhat depending upon the diameter of the seminiferous tubules, but such a discrimination could not be made in the adult rats. In the adolescent rats, small cells were less frequently observed than large and medium cells. This ratio of appearance was less marked in the adult rats. Clones from the same spermatogonial cells showed similar topography in both groups of rats as follows. The clones of a few medium cells were arranged singularly(As) or in pairs (Apr), but the clones of most medium cells appeared to form single cords (Aal) through intercellular bridges, while those of the small cells formed an open polygonal network as a large syncytium.

Age Factors

The effect of brown fat removal on the development of obesity in Zucker and Osborne-Mendel rats.

Removal of significant amounts of brown fat in young Zucker rats maintained at room temperature triggered compensatory changes in the remaining brown fat depots. These changes, which occurred to a greater extent in the lean than in the obese rats, enhanced the thermogenic potential of the remaining depots, thus possibly accounting for the lack of increased adiposity in these lipectomized rats. When the Zucker rats were maintained in the cold, rather than at room temperature, their ability to compensate for removal of the scapular brown fat was compromised, particularly in the obese animals. Under such conditions, the amount of functional brown fat was significantly reduced, and the amount of body fat elevated. In the lipectomized Zucker rats, this increase in adiposity was accompanied by increased body mass. In contrast, in the cold-exposed Osborne-Mendel rats, where lipectomy was not accompanied by compensatory increases in the mass and cellularity of the remaining brown fat depots, increased body fat occurred in the absence of any increase in food intake or in total body mass.

Adipose Tissue, Brown

Alterations in tight junctions of human endometrial epithelial cells during normal menstrual cycle--freeze-fracture electron microscopic study.

The structural change in the tight junction between human endometrial epithelial cells during the normal menstrual cycle was observed by means of freeze-fracture replica electron microscopy. Tight junctions between epithelial cells of the endometrial basal layer showed no alterations in structure during the menstrual cycle, while those between epithelial cells of the functional layer exhibited remarkable changes synchronized with the menstrual cycle; in the early proliferative phase, the tight junctions were composed of strands running mainly parallel to the luminal surface and the depth of the junctions from the luminal surface was 0.57 +/- 0.04 micron (Mean +/- S.E.), whereas in the late proliferative phase the junction formed a prominent network of strands 0.80 +/- 0.04 micron deep. In the early secretory phase, the junctions developed mostly as a complex network, and the depth was 0.96 +/- 0.04 micron. In the late secretory phase, the network consisting of the junctions looked disorderly and the depth of the junctions was reduced to 0.71 +/- 0.04 micron. As a conclusion, it was suggested that the tight junction in the human endometrial epithelium tended to develop or diminish according to the phase of the menstrual cycle.

Endometrium

Lipoprotein lipase activity and cellularity in brown and white adipose tissue in Zucker obese rats.

The genetically obese adult Zucker rat (fafa) exhibits reduced thermogenesis when stimulated by physiological agents (cold, catecholamines). Recent evidence suggests that this thermogenic defect may be important in the manifestation of the animal's obesity and that it reflects a reduced thermogenic contribution from brown adipose tissue, the major nonshivering thermogenic site in many mammals. The present study describes the effects of the obese genotype on brown (and white) adipocyte size, number, and lipid content and tissue lipoprotein lipase (LPL) activity. In the obese rats, brown fat depots were increased in mass. This increase could be accounted for by brown fat hypertrophy (due primarily to an increase in the amount of triglyceride present in each cell) rather than hyperplasia (there being no increase in the number of brown fat cells). In addition, unlike the situation in white fat, the brown fat from the obese rats did not exhibit higher LPL activity than did the brown fat from their lean littermates. This absence of an increased capacity for triglyceride uptake, coupled with the greater amount of triglyceride per brown adipocyte, is consistent with a reduction of triglyceride oxidation (and, thus, heat production) in the cells from the obese (v the lean) rats.

Adipose Tissue

Scapular brown fat removal enhances development of adiposity in cold-exposed obese Zucker rats.

To investigate the contribution of brown fat (BAT) to the development of obesity in genetically obese Zucker rats (fa/fa), scapular brown fat (SBAT) was removed from obese and lean 4-wk-old females. Eight weeks after surgery there was no regrowth of SBAT. Lipectomy had no effect on body weight gain, food intake, and body composition when rats were housed at 25 degrees C. Lean rats completely compensated for the lipectomy by increasing BAT mass, protein, cellularity, and activity of citrate synthase (CS) in axillary, perirenal, and thoracic depots. beta-Hydroxyacyl-coenzyme A dehydrogenase (HOAD) activity was increased, but compensation was incomplete. In lipectomized obese rats, only BAT protein and cell number were increased sufficiently for complete compensation. In a second experiment SBAT was removed from obese and lean rats, but rats were housed in the cold (10 degrees C) for 8 wk. In lean rats, although compensation was incomplete, it was sufficient to maintain a weight gain and body composition comparable with sham-operated lean rats. In obese rats, where there was little or no compensation for lipectomy, weight gain and fat deposition were greater than observed in sham-operated obese controls. These data support the hypothesis that reducing the amount of functional BAT contributes to the development of increased adiposity.

3-Hydroxyacyl CoA Dehydrogenases

[Effects of 4-(o-benzylphenoxy)-N-methylbutylamine hydrochloride (MCI-2016) on monamine metabolism in the brain].

Effects of MCI-2016 on the uptake, contents and turnover rate of monoamines were studied in the rat brain. MCI-2016 exhibited more potent inhibitory effect on the noradrenaline (NA) uptake than on dopamine (DA) and serotonin (5-HT) uptake. Especially, the inhibitory effect of MCI-2016 on the NA uptake in the hypothalamus was comparable to that of imipramine with the IC50 value of 4 X 10(-8) M. The levels of NA and its metabolite, MHPG-SO4, in the whole brain were significantly increased by 30 mg/kg, i.p. of MCI-2016. The peak effects were reached between two to 4 hrs after administration. The increase in 5-HT contents at the cortex were also observed by MCI-2016 (30 mg/kg, i.p.), with little changes in 5-HIAA contents. The levels of DA, HVA and DOPAC in the whole brain were not significantly influenced by MCI-2016. The turnover rate of NA was facilitated by 61.1% by 15 mg/kg, i.p. of MCI-2016. DA and 5-HT turnover rates were little affected by the same dosage of MCI-2016. In the case of imipramine (15 mg/kg, i.p.), however, it didn't increase the NA turnover, and in addition, it inhibited the 5-HT turnover. The increase in NA turnover rate induced by MCI-2016 was antagonized by 54.5% by 30 mg/kg, i.p. of atropine. Physostigmine (1 mg/kg, i.p.) also increased NA turnover rate which was also partially (62.6%) inhibited by atropine. These results may suggest that the effects of MCI-2016 on noradrenergic mechanisms were qualitatively different from those of tricyclic antidepressants. In addition, the results with atropine on the turnover rate may in part suggest a possible participation of the cholinergic mechanism on the turnover increasing effect of MCI-2016.

Animals